Thread-cutter.



J. DOWD. THREAD CUTTER.

APPLICATION FILED JUNE 5, 1913.

1,095,090, Patented Apr. 28, 1914.

WITNESSES INVENTOI? C7071 C/ZDOWd WWLIL By W v Q ATTORNEYS.

COLUMBIA PLANOGRAPH (to-,WASHINBTON. D. c.

WNTTED STATES PATENT OFFICE.

JOHN A. DOWD, OF FALL RIVER, MASSACHUSETTS.

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Specification of Letters Patent.

Original application filed August 13, 1912, Serial No. 714,889. Dividedand this application filed June 5, 1913. Serial No. 771,891.

To all whom it may concern:

Be it known that 1, JOHN A. Down, a citizen of the United States, and aresident of Fall River, in the county of Bristol and State ofMassachusetts, have invented a new and Improved Thread-Cutter, of whichthe following is a full, clear, and eXact description.

This invention relates to improvements in thread cutters, and is adivisional applica tion from my co-pending application for patententitled Thread cutting attachment, filed August 13, 1912, and bearingSerial Number 714,889.

The object of the invention is to provide an improved structure whichmay continually operate for cutting threads onpipes, bars, or the like,and form spaced threaded portions on a given article.

Another object of the invention is to provide a cutter with a threadedperipheral surface which may have said peripheral surface arranged invarious forms 50 as to produce a diii'erent arrangement of threads on agiven article or bar.

A still further object of the invention is to provide a cutter arrangedwith the cut ting threads or spurs at different distances from thecenter of the cutter so as to out either straight or tapering threads onthe tube or bar in a continuous operation, these threads or spurs beingeither formed in spaced banks or in banks contacting with each other.

In carrying out the objects of the invention, a substantially circularor disk-shaped body is provided, formed with cutting threads on theperipheral part thereof, and arranged to engage a bar, tube, or thelike, for cutting threads thereon and acting continuously. The cuttersforming the subject matter of the invention are substantially circularin shape, but have their cutting surfaces or faces arranged in banks atangles to each other in order to cut tapering threads without any changein any of the parts. The various banks of cutting threads may be, ifdesired, difierently arranged, as for instance abutting or spaced apart,however retaining the idea of some of the threads being farther from thecenter of the tool than others, which gives the desired taper when thetool is advanced faster than the proportionate rotation of the articlebeing threaded.

Apractical embodiment of the invention is represented in theaccompanying drawings forming a part of this specification in whichsimilar characters of reference indicate corresponding parts in all theviews.

Figure 1 is a fragmentary sectional View of a polygonal cutter and apartially threaded pipe; and Fig. 2 is a front view of the cutter withspaced banks of threads, the same being associated with the pipepartially threaded.

Referring to the accompanying drawings by numerals, 1 indicates a pipe,and 2 the cutter. It will be, of course, understood that the cutter 2could cut threads upon bars and other articles as well as a pipe, sothat the term pipe will be understood as meaning any article adapted tohave threads cut thereon.

On the periphery of the cutter are arranged a plurality of banks ofcutting threads 6, these banks being formed straight and meeting atpoints 8, whereby certain parts of each bank of cutting threads isfarther from the center of the cutter 2 than the other part. This willcause the sections of pipe 1 to be threaded with a taper, or rather witha double taper. It will be observed that the threads on all of thecutters disclosed are on the periphery, whereby a maximum speed may beattained without injury to the cutter or to the various threads thereof.A suitable driving member may be connected in any desired way with thecutter, as for instance by being keyed thereto so that the cutter may berotated at any desired rate, while the pipe 1 is also rotated.

In Fig. l will be seen another form of cutter, wherein there is providedbanks of cutting threads 10 on the cutter 11, these banks being spacedapart by suitable smooth portions 12 closer to the center of the cutter11 than the lowest thread on any of the banks 10. It will be evidentthat the portions 12 could be flush with the bottom of the lowest threadof the banks 10 without departing from the spirit of the invention.

which the cutters are mounted Each bank of cutting threads 10 is formedwith a point or high portion 13 farther from the center of the cutter 11than the re maining parts of the particular bank. The threads of thebanks 10 may approach the center of the cutter 11 in the are of acircle, or on a straight line drawn at a tangent. The cutter 11 may beconnected with a rotating shaft in any desired manner, as for instanceby being keyed thereto so that the cutter may rotate as pipe 14 rotates.By varying the ratio of rotation of pipe l t, and cutter 11, the lengthof the bevel or tapering threaded portions may be varied, and also.

the unthreaded portion or space on the pipe 14 between the threadedportions may be varied. This is very desirable where short pipes aredesired to be threaded on both ends, or where an extra long nipple isdesired where no threads are necessary in the center part. In thestructure shown in Fig. 1, the same is designed to thread the entirenipple and to cause the opposite ends of the nipple to be beveled inopposite directions.

In operation and in using the various cutters, the same are designed tobe mounted upon a traveling carriage which will move the cutterslongitudinally of the pipes being threaded, and which will at the sametime rotate the cutters. The power driving the carriage on which thecutters are mounted also rotates the pipe so that both the pipe andcutter are rotated in any desired ratio. The form of the cutter shown inFig. 2 is designed to produce short sections with threaded ends and aclear or unthreaded portion centrally. It will be observed that theunthreaded portion on the cutter is not equal to the unthreaded portionon the nipple or section of the pipe being cut, and that the taperthreaded on the cutter is not equal to the length of the taper threaded011 the nipple. The reason for this is that if the carriage on which thecutter is mounted advances at a rate of speed equal to the advancementof the thread which is being cut, the cutters will cut a substantiallystraight thread. If the carriage that is carrying the cutter wasreleased so as to not be driven but be permitted to move freely ineither direction, the continued rotation of the pipe would cause thecutter to revolve backward, the threaded portion acting as a worm andthe cutter acting as a worm gear. However, if the carriage is advancedat a speed greater than the advancement of the thread which is beingcut, then the rotary cutters will re volve ahead and this is necessaryin cutting tapering threads in order to bring the ilferent points of thecutter on the work which is being threaded. If the carriage on isadvanced at a rate of speed equal to twice the advancement of thethread, the space on the cutter Will be equal to half the space on thenipple, or both, and the length of the taper on the thread will be equalto hall. of the taper on the threaded section being cut. The cutters canbe driven or advanced at any rate of speed greater than the advancementof the thread, but for practical work not greater than the advancementof the work multiplied by the number of the out ters.

From this it will be observed that various cutters may be used atdifferent times and may be caused to advance at different speedsaccording to various circumstances, and the particular variety desired,namely whether the sections or nipples are to be beveled on the end orwhether or not the thread is to extend from one end of the nipple to theother. It will b observed that any desired number of cutters can be usedfor threading a given work, and. consequently a maximum speed may beutilized without in any way injuring the work or the machine.

Having thus described my invention I claim as new and desire to secureby Letters Patent 1. In a cutter of the class described, a body portionformed with spaced banks of cutting threads on the periphery, each bankof threads being set at an angle to the next adjacent bank of threads.

2. In a device of the character described, a cutter formed cylindrical.or disk-shaped, said cutter having threads on the periphery, saidthreads being arranged in spaced sets of banks, each set of banks beingsubstantially V-shaped.

3. In a device of the character described, a cutter formed with a bodyhaving spaced banks of threads on the periphery, said threads beingstruck on the arc of a circle substantially conforming to the workdesigned to be cut, and with a pitch correspending to the size of thethreads.

4:. A cutter formed with a substantially disk-shaped body having spacedbanks of cutting threads on the periphery, the threads of each bankbeing arranged substantially as a unit and said banks of cutting threadsbeing set at such an angle to each other as to form successive raisedthreaded portions.

5. In a device of the character described, a substantiallycircularcutter having spaced raised portions on the peripheral face of thecutter, said spaced raised portions being threaded on their peripheralface.

6. In a device of the character described, a substantially circularcutter formed of a single piece having spaced raised portions havingdiverging threaded surfaces, said threaded surfaces being formed on theperipheral face of the cutter.

In a device of the character described, a substantially circular cutterformed of a single piece having spaced threaded raised portions, thecenter of said portions being -farthest from the center of the cutter,said I gent and the threads in each bank being arthreaded raisedportlons being formed on ranged as a unit.

the peripheral face of the cutter, the threads In testimony whereof Ihave signed my of said portions being arranged substanname to thisspecification in the presence of tially in a straight line. twosubscribing Witnesses.

S. In a device of the character described, a substantially circularcutter formed of a JOHN DOWD' single piece having banks of cuttingthreads Witnesses: set at an angle to each other, each of said J 01in T.MoniAn'rY, 10 banks of cutting threads being set at a tan- JOHN T.CAREY.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

